RF lens antenna array with reduced grating lobes

Abstract

A radio frequency antenna array uses lenses and RF elements, to provide ground-based coverage for cellular communication. The antenna array can include two spherical lenses, where each spherical lens has at least two associated RF elements. Each of the RF elements associated with a given lens produces an output beam with an output area. Each lens is positioned with the other lenses in a staggered arrangement. The antenna includes a control mechanism configured to enable a user to move the RF elements along their respective tracks, and automatically phase compensate the output beams produced by the RF elements based on the relative distance between the RF elements.

What is claimed is: 
     
       1. A communication system, comprising:
 at least first and second lenses within an array of lenses; 
 the first lens has a first RF element oriented to produce a first output beam, 
 the second lens has a second RF element oriented to produce a second output beam; 
 a controller is configured to combine at least the first and second output beams to produce a first overlapped beam; 
 wherein the controller configured to phase shift the first output beam and the second output beam into an equal phase; 
 wherein the controller is further configured to electrically phase shift at least the first and second output beams to effectively move the first overlapped beam across an output area; and, 
 wherein the controller is further configured to position the first RF element independent of the second RF element. 
 
     
     
       2. The communication system of  claim 1  further comprising a third lens having a third RF element oriented to produce a third output beam;
 wherein the controller is configured to combine at least the first overlapped beam, and third output beams to produce a second overlapped beam, by constructive interference; and 
 wherein the controller is further configured to electronically phase shift at least one of the first, second, and third output beams to effectively track a target with the second overlapped beam. 
 
     
     
       3. The communication system of  claim 2 , wherein the third lens is collinear with first and second lenses. 
     
     
       4. The communication system of  claim 2 , wherein at least one of the first lens, the second lens, and third lens are spherical. 
     
     
       5. The lens array of  claim 1 , wherein each of the first lens and the second lens comprises a Luneburg lens. 
     
     
       6. The communication system of  claim 1 , wherein at least one of the first RF element and the second RF element is configured to electronically phase compensate to effectively reduce azimuth side lobe levels of the first overlapped beam. 
     
     
       7. The communication system of  claim 1 , wherein at least one of the first RF element and the second RF element is configured for dual-polarization. 
     
     
       8. The communication system of  claim 1 , further comprising a first sub-controller coupled to the controller, wherein the first sub-controller is configured to (i) receive an instruction from the controller, and (ii) electronically phase shift the first output beam based on the instruction. 
     
     
       9. The communication system of  claim 1 , wherein the first output beam is configured for a first beam width, and the second output beam is configured for a second beam width. 
     
     
       10. The communication system of  claim 9 , wherein the first beam width is the same as the second beam width. 
     
     
       11. The communication system of  claim 9 , wherein the first beam width is different than the second beam width. 
     
     
       12. The communication system of  claim 1 , wherein the second RF element is configured to generate the second output beam at an azimuth off-normal from the horizon of at least one of the first lens and the second lens. 
     
     
       13. A communication system, comprising:
 at least first and second lenses within an array of lenses, 
 wherein the first lens is arranged on a first plane parallel to a ground; 
 the first lens has a first RF element oriented to produce a first output beam; 
 the second lens has a second RF element oriented to produce a second output beam; 
 a controller is configured to combine at least the first and second output beams to produce a first overlapped beam; 
 wherein the controller is further configured to electronically phase shift at least the first and second output beams to effectively move the first overlapped beam across an output area; 
 wherein the controller is configured to phase shift the first output beam and the second output beam into an equal phase; 
 wherein the second RF element is arranged on a second plane; and, 
 wherein the second plane is offset perpendicularly from the first plane by a distance. 
 
     
     
       14. The communication system of  claim 13 , wherein the distance is at least equal to 50% of a height of the first lens from the first plane. 
     
     
       15. The communication system of  claim 13 , wherein the distance is at most equal to 100% of a height of the first lens from the first plane. 
     
     
       16. The communication system of  claim 13 , further comprising a third lens having a third RF element oriented to produce a third output beam, wherein the first, second, and third RF element are aligned on a third plane that is perpendicular to both the first and second planes. 
     
     
       17. The communication system of  claim 16 , wherein the third lens is collinear with first and second lenses. 
     
     
       18. The communication system of  claim 16 , wherein the second plane is different from the first plane. 
     
     
       19. The communication system of  claim 13 , wherein at least one of the first RF element and the second RF element is configured for dual-polarization. 
     
     
       20. The communication system of  claim 13 , further comprising a first sub-controller coupled to the controller, wherein the first sub-controller is configured to (i) receive an instruction from the controller, and (ii) electronically phase shift the first output beam based on the instruction. 
     
     
       21. The communication system of  claim 13 , wherein the first output beam is configured for a first beam width, and the second output beam is configured for a second beam width. 
     
     
       22. The communication system of  claim 21 , wherein the first beam width is the same as the second beam width. 
     
     
       23. The communication system of  claim 21 , wherein the first beam width is different than the second beam width.